The present invention relates to an elevator system and especially a system for controlling a plurality of parallel elevators.
With the spread of elevator and in accordance with the current tendency of loftiness of building, there is an increasing demand for a higher reliability for the elevator controller, not to mention the safety, because the elevator has an important role of a vertical transportation means of the whole building.
In addition, the steady progress of the technique has brought about improved durability of the building and the elevator itself. Consequently, it is often experienced that the elevator controller is repaired or renewed before the lives of the building and the elevator expire. More specifically, there are many cases that an elevator car control device or a system control device which have worked ten years or so. Generally, in such a case, whole part of the elevator controller, which weighs tens of hundred kilogrammes to 1 ton is renewed with new one assembled in the factory. The entire elevator system has to be stopped during such a replacement which takes a considerably long time.
In addition, if a trouble is caused in the system control device, the whole elevator system becomes inoperative and unserviceable. Such an inconvenience has to be overcome.
Further, the replacement or renewal of the hall-call register, due to breakage of malfunctioning of the same, and the protective maintenance of the system control device have to be done in the nighttime in which there is no traffic demand. This problem is serious particularly when the number of elevators to be maintained is large.
Hereinafter, shortcomings or problems of the prior art will be described.
Suppose an elevator system has parallel elevator cars. These elevator cars are adapted to be controlled by respective elevator car control devices to which electric power for driving respective elevator cars is supplied from respective lead-in power supplies.
Referring first to the reliability of operation of the elevator system, it is to be pointed out that whole part of the elevator system becomes inoperative, if a breakdown takes place in the system control device, since the interface controlling circuit is combined in the system control device. Further, if there is any trouble in the common power supply circuit or in the hall-call registers or in the observation panel, whole or a part of the elevator system becomes out of use. Since in most cases there is no system backup for supporting the elevator control system, the only measure left for improving the reliability of the elevator system is to enhance the reliabilities of respective parts of the elevator system.
As a matter of fact, however, the control system consists of some hundreds of relays or incorporates micro-processors the reliability of which has not been settled yet. Consequently, the control system is not always reliable enough. In addition, since the construction of the control system is highly complicated, the down time inevitably becomes long, in case of a breakdown of the control system. This causes a serious problem because all of the elevator cars cannot respond to the hall-call during such a long down time.
Referring now to the renewal of part of the control system and to the protective maintenance of the same, the number of signals exchanged between the elevator car control devices and the system control device is about 200 to 300 for each elevator car, when the number of floors is 15 or so, although it depends on the kind of controlling system and the number of floors served by the elevator cars.
Recently, an improved elevator controlling system has been proposed, in which for the adoption of IC for serial transmission, the above-mentioned large number of signals are transmitted through only several wires. By adopting this newly developed technique, it is possible to minimize the number of wires between the control devices.
However, it is not impossible to eliminate some 200 to 300 lines interconnecting each elevator controller, and the elevator car, motor and its accessories in the machinery room and safety switches, position detectors and so forth in the elevator shaft. Therefore, it takes a long time for renewing the elevator car control device. In addition, it is almost impossible to install the terminals on the newly assembled elevator car operaion control device in the order strictly identical to that of the old elevator car operation control device to be removed. It is therefore necessary to alter the wiring suitably to meet the terminal arrangement of the newly assembled elevator car operation control device when the latter is installed. Further, the correct connection of the wiring must be confirmed after the completion of the work, through a strict inspection and trial.
Usually, the common power supply circuit and the whole or a part of managing and controlling circuit are installed in the same cubicle with the car operation control devices. It is therefore necessary to cut off the power supply to all elevator cars, when one of the cars is repaired or renewed.
As to the standardization of the elevator car operation control device the hall-call signal is delivered to the system control device in case that the elevator system has a plurality of parallel elevator cars. However, in case the elevator system has only one elevator car, it is necessary to install the hall-call interface controlling circuit and hall-call registration circuit within the elevator car operation control device because in such a case there is no system control device.
To cope with above-stated two different kinds of demand, it has been necessary to design and produce two types of elevator car operation control devices for a single elevator and parallel elevators, resulting in a raised cost of design and administration, which is quite inconvenient from the view point of mass production. Regarding an elevator system it has been proposed as described in Japanese laid-open patent application No. 51 (1976)-53354 and corresponding U.K. Pat. No. 1515339 to provide with interface controlling means constituting a part of system control device, which directly takes up the hall-call singnals from a hall-call register located on every floor to register the hall-calls.
Further, regarding an elevator system it has been proposed as described in Japanese laid-open patent application 49 (1974)-126054 and corresponding U.S. Pat. No. 3854554, to provide with interface controlling means constituting a part of system control device. According to the construction as above-described, it is to be pointed out the whole part of the elevator system becomes inoperative, if a breakdown takes place in the system control device, since the interface controlling means is combined in the system control device. Further it is unconvenient to make the renewal of the car operation control device or the system control device and the maintenance of the same, and it is impossible to provide the commonness for a single elevator and parallel elevators to effect the standardization of the elevator car operation control devices.